/* ----------------------------------------------------------------------
* Copyright (C) 2010 ARM Limited. All rights reserved.
*
* $Date:        15. February 2012
* $Revision: 	V1.1.0
*
* Project: 	    CMSIS DSP Library
* Title:	    arm_cmplx_mult_real_q31.c
*
* Description:	Q31 complex by real multiplication
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Version 1.1.0 2012/02/15
*    Updated with more optimizations, bug fixes and minor API changes.
*
* Version 1.0.10 2011/7/15
*    Big Endian support added and Merged M0 and M3/M4 Source code.
*
* Version 1.0.3 2010/11/29
*    Re-organized the CMSIS folders and updated documentation.
*
* Version 1.0.2 2010/11/11
*    Documentation updated.
*
* Version 1.0.1 2010/10/05
*    Production release and review comments incorporated.
*
* Version 1.0.0 2010/09/20
*    Production release and review comments incorporated.
* -------------------------------------------------------------------- */

#include "arm_math.h"

/**
 * @ingroup groupCmplxMath
 */

/**
 * @addtogroup CmplxByRealMult
 * @{
 */


/**
 * @brief  Q31 complex-by-real multiplication
 * @param[in]  *pSrcCmplx points to the complex input vector
 * @param[in]  *pSrcReal points to the real input vector
 * @param[out]  *pCmplxDst points to the complex output vector
 * @param[in]  numSamples number of samples in each vector
 * @return none.
 *
 * <b>Scaling and Overflow Behavior:</b>
 * \par
 * The function uses saturating arithmetic.
 * Results outside of the allowable Q31 range[0x80000000 0x7FFFFFFF] will be saturated.
 */

void arm_cmplx_mult_real_q31(
    q31_t* pSrcCmplx,
    q31_t* pSrcReal,
    q31_t* pCmplxDst,
    uint32_t numSamples)
{
	q31_t inA1;                                    /* Temporary variable to store input value */

#ifndef ARM_MATH_CM0

	/* Run the below code for Cortex-M4 and Cortex-M3 */
	uint32_t blkCnt;                               /* loop counters */
	q31_t inA2, inA3, inA4;                        /* Temporary variables to hold input data */
	q31_t inB1, inB2;                              /* Temporary variabels to hold input data */
	q31_t out1, out2, out3, out4;                  /* Temporary variables to hold output data */

	/* loop Unrolling */
	blkCnt = numSamples >> 2u;

	/* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
	 ** a second loop below computes the remaining 1 to 3 samples. */
	while(blkCnt > 0u) {
		/* C[2 * i] = A[2 * i] * B[i].            */
		/* C[2 * i + 1] = A[2 * i + 1] * B[i].        */
		/* read real input from complex input buffer */
		inA1 = *pSrcCmplx++;
		inA2 = *pSrcCmplx++;
		/* read input from real input bufer */
		inB1 = *pSrcReal++;
		inB2 = *pSrcReal++;
		/* read imaginary input from complex input buffer */
		inA3 = *pSrcCmplx++;
		inA4 = *pSrcCmplx++;

		/* multiply complex input with real input */
		out1 = ((q63_t) inA1 * inB1) >> 32;
		out2 = ((q63_t) inA2 * inB1) >> 32;
		out3 = ((q63_t) inA3 * inB2) >> 32;
		out4 = ((q63_t) inA4 * inB2) >> 32;

		/* sature the result */
		out1 = __SSAT(out1, 31);
		out2 = __SSAT(out2, 31);
		out3 = __SSAT(out3, 31);
		out4 = __SSAT(out4, 31);

		/* get result in 1.31 format */
		out1 = out1 << 1;
		out2 = out2 << 1;
		out3 = out3 << 1;
		out4 = out4 << 1;

		/* store the result to destination buffer */
		*pCmplxDst++ = out1;
		*pCmplxDst++ = out2;
		*pCmplxDst++ = out3;
		*pCmplxDst++ = out4;

		/* read real input from complex input buffer */
		inA1 = *pSrcCmplx++;
		inA2 = *pSrcCmplx++;
		/* read input from real input bufer */
		inB1 = *pSrcReal++;
		inB2 = *pSrcReal++;
		/* read imaginary input from complex input buffer */
		inA3 = *pSrcCmplx++;
		inA4 = *pSrcCmplx++;

		/* multiply complex input with real input */
		out1 = ((q63_t) inA1 * inB1) >> 32;
		out2 = ((q63_t) inA2 * inB1) >> 32;
		out3 = ((q63_t) inA3 * inB2) >> 32;
		out4 = ((q63_t) inA4 * inB2) >> 32;

		/* sature the result */
		out1 = __SSAT(out1, 31);
		out2 = __SSAT(out2, 31);
		out3 = __SSAT(out3, 31);
		out4 = __SSAT(out4, 31);

		/* get result in 1.31 format */
		out1 = out1 << 1;
		out2 = out2 << 1;
		out3 = out3 << 1;
		out4 = out4 << 1;

		/* store the result to destination buffer */
		*pCmplxDst++ = out1;
		*pCmplxDst++ = out2;
		*pCmplxDst++ = out3;
		*pCmplxDst++ = out4;

		/* Decrement the numSamples loop counter */
		blkCnt--;
	}

	/* If the numSamples is not a multiple of 4, compute any remaining output samples here.
	 ** No loop unrolling is used. */
	blkCnt = numSamples % 0x4u;

	while(blkCnt > 0u) {
		/* C[2 * i] = A[2 * i] * B[i].            */
		/* C[2 * i + 1] = A[2 * i + 1] * B[i].        */
		/* read real input from complex input buffer */
		inA1 = *pSrcCmplx++;
		inA2 = *pSrcCmplx++;
		/* read input from real input bufer */
		inB1 = *pSrcReal++;

		/* multiply complex input with real input */
		out1 = ((q63_t) inA1 * inB1) >> 32;
		out2 = ((q63_t) inA2 * inB1) >> 32;

		/* sature the result */
		out1 = __SSAT(out1, 31);
		out2 = __SSAT(out2, 31);

		/* get result in 1.31 format */
		out1 = out1 << 1;
		out2 = out2 << 1;

		/* store the result to destination buffer */
		*pCmplxDst++ = out1;
		*pCmplxDst++ = out2;

		/* Decrement the numSamples loop counter */
		blkCnt--;
	}

#else

	/* Run the below code for Cortex-M0 */

	while(numSamples > 0u) {
		/* realOut = realA * realB.            */
		/* imagReal = imagA * realB.               */
		inA1 = *pSrcReal++;
		/* store the result in the destination buffer. */
		*pCmplxDst++ =
		    (q31_t) clip_q63_to_q31(((q63_t) * pSrcCmplx++ * inA1) >> 31);
		*pCmplxDst++ =
		    (q31_t) clip_q63_to_q31(((q63_t) * pSrcCmplx++ * inA1) >> 31);

		/* Decrement the numSamples loop counter */
		numSamples--;
	}

#endif /* #ifndef ARM_MATH_CM0 */

}

/**
 * @} end of CmplxByRealMult group
 */
